EFFECTS OF MALE REMOVAL ON FEMALE REPRODUCTIVE-BIOLOGY IN ROSS AND LESSER SNOW GEESE

We studied effects of mate removal on nesting and hatching success, in cubation behavior, body mass, and post-hatch dispersal distance of fem ale Ross' (Chen rossii) and Lesser Snow Geese (C. caerulescens caerule scens) at Karrak Lake, N.W.T., Canada. Male geese were removed during early incubation (days 1-8), and widowed and paired control females we re monitored through post-hatch dispersal. Nesting and hatching succes s did not differ between species or treatments (widowed vs paired) and averaged 77.5 +/- 3.8% and 64.0 +/- 3.6% (+/-SE). respectively. Paire d females spent more time with their bills tucked (23.7 +/- 3.3% vs 9. 1 +/- 4.0%) and less time alert (8.6 +/- 2.9% vs 22.9 +/- 3.5%) while on nests than did widowed females. Snow widowed females (31.1 +/- 4.7% ) and Ross' widowed females (20.6 +/- 6.0%) generally spent more time each day in head-up alert than did Snow paired females (7.1 +/- 3.8%), Snow paired males (11.8 +/- 3.8%), Ross' paired females (9.4 +/- 3.6% ), and Ross' paired males (7.9 +/- 3.6%). Body mass of paired and wido wed female Ross' Geese did not differ at hatch or at time of post-hatc h recapture; however, mean distance recaptured from the breeding colon y was greater for paired (50.9 +/- 6.1 km) than for widowed females (2 7.3 +/- 6.6 km). Total mass gain (276 +/- 19 g) and rate of mass gain (8.4 +/- 0.5 g/day), from hatch until post-hatch recapture (33.1 +/- 1 .2 days), were similar for widowed and paired female Ross' Geese. Male removal experiments in monogamous, precocial species generally have p roduced few effects on female nesting success or incubation behavior W e suggest that male parental care in arctic-nesting geese is more crit ical during laying and the post-hatch period than during incubation.